Abstract
We demonstrate the detection of the Brownian relaxation frequency of 250 nm diameter magnetic beads using a lab-on-chip platform based on current lines for exciting the beads with alternating magnetic fields and highly sensitive magnetic tunnel junction (MTJ) sensors with a superparamagnetic free layer. The first harmonic out-of-phase component of the MTJ response gives the imaginary part of the magnetic bead susceptibility, which peaks at the Brownian relaxation frequency. This work paves the way to on-chip implementation of Brownian magnetorelaxometry in innovative "lab-on-a-bead" assays for biomolecular recognition. (C) 2011 American Institute of Physics. [doi:10.1063/1.3554374]
Original language | English |
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Journal | Applied Physics Letters |
Volume | 98 |
Issue number | 7 |
Pages (from-to) | 073702 |
ISSN | 0003-6951 |
DOIs | |
Publication status | Published - 2011 |